New Delhi: Sri Lanka Wednesday said the issue of Chinese submarines making a port call in Colombo was "not a threatening situation" and the vessels were returning from Africa.

Sri Lankan International Monetary Cooperation Minister Amunugama, in answer to a query on the sidelines of an event, said the Chinese submarines were returning from the Horn of Africa.

"All submarines are coming that way. It was not a threatening situation," he added.

Amunugama also said Sri Lanka was planning to build large fuel oil tanks at the Humbantota port, which has been built with Chinese aid, in order to provide refueling facilities to the hundreds of ships that pass that way.

Nuclear submarine Changzheng-2 and warship Chang Xing Dao docked at the Colombo port Friday. Earlier, another Chinese submarine, a long-range deployment patrol, had called at the same port ahead of Chinese President Xi Jinping's visit to the Maldives, Sri Lanka and India.

China has said its submarines making port calls in Colombo was "nothing unusual".

Indian strategic analysts have voiced concern over the frequent docking of Chinese naval ships in Sri Lanka.